781428531 has 8 divisors (see below), whose sum is σ = 1122051280. Its totient is φ = 480879072.

The previous prime is 781428517. The next prime is 781428539. The reversal of 781428531 is 135824187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 781428531 - 2¹⁷ = 781297459 is a prime.

It is a super-2 number, since 2×781428531² = 1221261098121635922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 20036629 = 781428531 / (7 + 8 + 1 + 4 + 2 + 8 + 5 + 3 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 781428531.

It is not an unprimeable number, because it can be changed into a prime (781428539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10018276 + ... + 10018353.

It is an arithmetic number, because the mean of its divisors is an integer number (140256410).

Almost surely, 2^781428531 is an apocalyptic number.

781428531 is a deficient number, since it is larger than the sum of its proper divisors (340622749).

781428531 is a wasteful number, since it uses less digits than its factorization.

781428531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20036645.

The product of its digits is 53760, while the sum is 39.

The square root of 781428531 is about 27954.0431959314. The cubic root of 781428531 is about 921.0780254584.

The spelling of 781428531 in words is "seven hundred eighty-one million, four hundred twenty-eight thousand, five hundred thirty-one".